This invention relates to an actuator arm gate opener for controlled swinging gates, specifically to gate hinges that lift the gate as the gate swings open.
Gates have been in use since before recorded history for both functional and aesthetic purposes in providing selected access. Most gates swing from a vertical post between an open and closed position. Gate hinges have been made available for attaining lift as a way to clear the rising path of contouring terrain immediately adjacent the gate. In prior art, hinges provide for only a small lift and do not allow for site conditions where the terrain steeply rises adjacent the gate. Until now the only available gates that can accommodate steep and/or snow site conditions are barrier gates that vertically rise above the path way and sliding gates that roll laterally in and out of the path way. In residential installations vertically lifting barrier gates and sliding gates are not aesthetically pleasing nor are they as practical to install as the traditional swinging gate.
A rear view of a prior art non-lifting gate is illustrated in FIG. 1 (rear view gate closed). The gate 110 is composed of a barrier element 112 attached to the top bracket 118 and the bottom bracket 122. The bearings 124 attach to the top hinge support 116 and the bottom hinge support 120. The hinge supports attach to the column 114. The prior art gate 110 is limited to opening and closing through a horizontal path. The prior art gate 110 is not effective in applications where the location of the gate is in uneven terrain such as sloped driveways and where obstacles such as snow will be present to obstruct the path of the gate.
Several different approaches to lifting a swinging gate include U.S. Pat. No. 4,658,543 to Carr (1987) which shows a complex hinge system that swings while a lifting cylinder lifts the gate simultaneously. This is an overly expensive and complex solution to a high lift swinging gate, and U.S. Pat. No. 5,050,344 to Skeem which uses a hydraulic lifting drum and sliding hinge pins to accomplish the same.
Although prior art does provide for different types of lifting hinges that utilize a rearward inclination of the top and bottom hinge axes to achieve lift during the opening rotation of the gate hinge. These gate hinges require proportionally more force to open the gate as the lift or rearward inclination of the hinge is increased. Examples of these lifting hinges include U.S. Pat. No. 4,233,708 to Bonar (1978) where a rearward inclination of gate hinge axes is on the side of the post and U.S. Pat. No. 5,592,717 to Longo (1997) where the same inclination of hinge axes is located at the back of the post, with a hinge rod and an impractical series of clamps and bolts to allow for limited adjustment of an additional skewing of the hinge axes to keep the gate from leaning back as it rotates and lifts.
All the lifting hinges utilizing rearward inclination of axes as cited above were not commercially successful and the heretofore known prior art suffers from a number of disadvantages: the higher the lift or rearward inclination of the hinge axes, the more force required to open the gate; the force to open and lift the gate is large enough to require that only smaller gates be used; once the gate is open there is always a danger that it can slam shut, the prior art has no counterbalancing of gate when it is open; gates that need to be lifted high have no commercially available openers that can track the geometry of the rising gate; low and high lift gates must be heavily made and structurally reinforced at the point of attachment of the gate opener to withstand the strong pull of the gate opener; gates don't initially lift as quickly as possible because the hinge geometry is not optimized; and the aesthetically unpleasing actuator must be located at the front or rear of the hinge bearing column to operate the gate.